/* 
 * Copyright 2001-2009 Terracotta, Inc. 
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not 
 * use this file except in compliance with the License. You may obtain a copy 
 * of the License at 
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0 
 *   
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 
 * License for the specific language governing permissions and limitations 
 * under the License.
 * 
 */

package org.go.spi.impl;

import java.io.InputStream;
import java.net.URL;

import org.go.spi.ClassLoadHelper;

/**
 * A <code>ClassLoadHelper</code> that uses either the context class loader
 * of the thread that initialized Quartz.
 * 
 * @see org.quartz.spi.ClassLoadHelper
 * @see org.quartz.simpl.ThreadContextClassLoadHelper
 * @see org.quartz.simpl.SimpleClassLoadHelper
 * @see org.quartz.simpl.CascadingClassLoadHelper
 * @see org.quartz.simpl.LoadingLoaderClassLoadHelper
 * 
 * @author jhouse
 * @author pl47ypus
 */
public class InitThreadContextClassLoadHelper implements ClassLoadHelper {

	/*
	 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	 * 
	 * Data members.
	 * 
	 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	 */

	private ClassLoader initClassLoader;

	/*
	 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	 * 
	 * Interface.
	 * 
	 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	 */

	/**
	 * Enable sharing of the class-loader with 3rd party.
	 *
	 * @return the class-loader user be the helper.
	 */
	@Override
	public ClassLoader getClassLoader() {
		return this.initClassLoader;
	}

	/**
	 * Finds a resource with a given name. This method returns null if no
	 * resource with this name is found.
	 * @param name name of the desired resource
	 * @return a java.net.URL object
	 */
	@Override
	public URL getResource(String name) {
		return initClassLoader.getResource(name);
	}

	/**
	 * Finds a resource with a given name. This method returns null if no
	 * resource with this name is found.
	 * @param name name of the desired resource
	 * @return a java.io.InputStream object
	 */
	@Override
	public InputStream getResourceAsStream(String name) {
		return initClassLoader.getResourceAsStream(name);
	}

	/**
	 * Called to give the ClassLoadHelper a chance to initialize itself,
	 * including the opportunity to "steal" the class loader off of the calling
	 * thread, which is the thread that is initializing Quartz.
	 */
	@Override
	public void initialize() {
		initClassLoader = Thread.currentThread().getContextClassLoader();
	}

	/**
	 * Return the class with the given name.
	 */
	@Override
	public Class loadClass(String name) throws ClassNotFoundException {
		return initClassLoader.loadClass(name);
	}
}
